The present invention concerns a handling process for staging manufactured articles leaving a production unit and travelling towards a receiving machine, e.g., a packaging unit working at a preset speed, and a facility for putting this process into effect.
Normally, when a production line delivers manufactured goods at a speed of its own and these goods have to be packaged by a machine also working at a rhythm of its own, a problem arises of synchronising the two operating cycles.
This problem is frequently solved by simply allowing the goods to accumulate in column in front of a barrier which opens and closes in synchronisation with the rhythm at which the packing machine works. The leading product may be separated from the column by various separating devices, synchronised with the packaging machine, or simply by synchronising the conveyor belt passing beneath the barrier with the speed of the packaging unit. A particular illustration of this type of separating device appears in the German patent application No. 2,243,906, published before examination.
However, this approach incorporates two major inconveniences, as follows:
The goods do not accumulate without producing a certain pressure along the line in which they are conveyed, due to the coefficient of friction of the conveyor belt against the base of the products accumulated in the column. This pressure may deform the goods at the head of the column and make them unsuitable for packaging.
Further, to prevent the goods leaving at the sides or piling on top of each other, the column must be surrounded with guides which hold the goods at the top and at the sides.
The friction between the base of the goods and the conveyor belt produces heat and wear on the two contact surfaces. Further, where foodstuffs are concerned, e.g., chocolate, there is some risk of the conveyor belt becoming soiled.
Another approach is to use a chain which moves in synchronisation with the packaging unit and includes a certain number of barriers staged exactly according to the operating cycles of the packaging machine. A particular illustration of this type of machine appears in Swiss Pat. No. 439,063, German patent application No. 1,288,509 published after examination, and the present holder's German Pat. No. 2,150,954. The goods are packaged on entering the facility in such a way that their rate is slightly higher than that of the barriers forming part of the chain. A detector system operates the barriers in such a way that they fall into the spaces separating the successive products along the conveyor belt. The speed of the belt being greater than that of the chain bearing the barriers, the goods move towards the barriers at a speed equal to the difference of the speed of the chain bearing the barriers, and that of the conveyor belt, up to the point of their impact against the said barriers. From that point, their rate is governed by the rate of the barriers forming part of the said chain.
This system, too, contains a number of inconveniences, particularly because the risk of soiling owing to friction between the base of the goods and the conveyor belt still exists. Furthermore, if the machine is to operate at a high speed, it must be equipped with a large number of barriers, which considerably increases the space taken up by the system.